/Engine/Source/Runtime/Datasmith/DatasmithCore/Public/IDatasmithSceneElements.h
Attach the actor to the scene root. Detach the actor if it was already attached.
void AttachActorToSceneRoot ( const [TSharedPtr](API\Runtime\Core\Templates\TSharedPtr)< [IDatasmithActorElement](API\Runtime\DatasmithCore\IDatasmithActorElement) > & Child, EDatasmithActorAttachmentRule AttachmentRule )